How sealing your concrete driveway helps you

1. Sealing minimize pebbles popping out from aggregate concrete by hardening surrounding cement
2. It minimizes erosion of cement from pressure washing and rain
3. Reduced cracking by strengthening concrete and encouraging water to flow off the surface
4. It slows weathering and breaking up of existing crack edges by hardening the concrete
5. The sealer reduces potential for staining (oil stains) because fewer air pores are available to be filled
6. Sealer seals driveway by providing a harder surface with fewer pores which makes cleanings easier.
7. It helps concrete look more uniform by increasing hardness and minimizing wear
8. Concrete sealer slows subconcrete soil erosion by keeping the surface water on top
9. Sealer hardens the concrete and makes it more resistant to wear
10. Sealer fills air pores, slows water absorbption and minimizes seepage of water to feed algae after the rains
11. Sealer slows growth of mildew in same way
12. It is safer to walk on because of reduced slipperiness from mildew and algae
13. Save money and time by going longer between concrete cleanings

Drip lines on driveway by garage door from gutter water eroding the concrete. Hardening the concrete with a sealer and keeping the gutters clean helps keep the concrete keep a more uniform appearance for longer.

What Concrete or Masonry Should Be Sealed

About Concrete

Concrete is made up of from coarse stone(gravel,pebbles), fine stone/sand, and a binder (Portland concrete). It is poured while wet into forms. The concrete is burped to remove air bubbles that may have gotten trapped in it. The concrete then cures and the forms can be pulled away. This leaves a hard surface. Concrete is rated according to its hardness. 3000 PSI is a typical concrete hardness. This means it can withstand 3000 pounds of pressure per square inch. This also means that it shouldn't be cleaned with a pressure washer that is going to deliver more than 3000 pounds per square inch.

Concrete has air pockets in it. Concrete is from 5-8 % air. This allows water to flow through the concrete. Since the concrete has a water-soluble binder, this water can leach out important chemicals that are holding the concrete together. Water acts like a solvent, slowly eroding and degrading the binding properties of the cement. In time, with enough water flow, the surface will erode, and the concrete eventually will crumble. How long this process takes depends on: water flow over and through the concrete, pressure-washing, things growing on concrete (mildew, algae, moss) and whether the concrete is sealed.

Sealing the concrete protects it from the damaging water. Concrete foundations if allowed to be saturated with water in the ground can crack. This cracking happens because the ground settles underneath the concrete and creates uneven pressures instead of cradling the foundation uniformly. Eventually over many years the foundation can rot and crumble. This is noticed in some older portland homes. This is why it's especially important to keep gutters working to protect your home's foundation.

One reason concrete driveway slabs crack is that water flows in channels under the concrete, eroding out little river beds so the soil doesn't support the concrete along this flow line. As the concrete is pulled to the earth's center by gravity, it may crack because there isn't soil to support it. Sealing concrete helps keep moisture out of the concrete driveway and allows the concrete to dry out quicker.

What Type of Sealer Should be Used

There are several types of concrete or masonry sealers: Acrylic (topcoat), Silica / Silicate (surface, and slightly penetrating) and long-lasting polyester.

I have access to wholesale prices on the best of these sealers, the polyester, because I purchase in large volumes. Polyester is the best sealer because it has a 10 year guarantee, penetrates the masonry or concrete to depth of up to 2 inches, hardens the surface and is not subject to UV damage in the way top coating sealers (acrylic, silicas, silicates) are exposed.

The Purpose of the Sealer

Asthetics

Durability of Concrete and Masonry Sealer

Making Concrete Easier to Clean

Don't Seal Any Concrete You Don't Want to Keep

Any concrete that you do not want to keep for a long time should not be treated. Otherwise when the sealer hardens the concrete, it makes it more difficult to break up, cut and remove. Examples of concrete you may not want to keep are slabs that have been broken by heavy trucks and concrete to which a deicer has been applied. These broken pieces or crumbling pieces of concrete should be removed and repoured.

Concrete Preparation Before Sealing

Concrete that is to be sealed must first be cleaned and degreased. Pressure-washing is usually done first and then any stain removal. Some deep stains (10 yr car oil drip) may come out on the top, but after the sealer is applied, the heat from sun etc will draw oils from deeper concrete to the surface so that stain reappears again. This is something to be aware of. Since the sealer needs to penetrate the concrete, a cleaner/degreaser is recommended to remove oils that may keep the sealer from going into the pores of the concrete to be sealed.

Sealing Concrete and When to Seal Concrete

Under normal conditions, late spring, early summer or cooler days in summer, and fall are best times to apply sealer. It needs dry enough weather for concrete to dry out from pressure-washing and cool enough weather that the sealer will not flash dry on the surface before it's had time to soak into the concrete. The concrete sealer needs to be applied quickly and evenly so that the concrete sealer is overlapped wet to wet and doesn't band on the concrete surface. While a person can seal their own concrete with a hand pump, for any large surface area it makes more sense to use an electric sprayer.

Helping Your Concrete Look Nicer Longer between Cleanings

When water falls from the sky onto your concrete, the concrete needs to be able to shed the water. A healthy slope on the concrete is important. Also, the area where the water flows needs to be lower than the concrete. If there is dirt and grass bermed up onto the concrete or along its edge then the water will not be able to escape in a timely manner. Putting even a shallow trough about 4-6 inches wide around the concrete will go a long way to keeping the concrete cleaner. This trough can be filled with coarse stone or rocks.

The ground and concrete above another pad of concrete must drain water properly away from lower concrete. Muddy water flowing onto the top part of a driveway will get the rest of the driveway dirty below it. If the concrete is cleaned and sealed, it makes sense to take simple steps to keep contaminants from getting it dirty again.

Dirt is eroding from the barkdust walkway onto the concrete driveway below. Simply having a 6-8 inch trench filled with rock between the path and the driveway would help keep this driveway cleaner.

At some homes, the downspouts are disconnected from drains to help keep the city's sewers from overflowing into the rivers. Water from downspouts need to be directed away from the foundation (for sure) and hopefully not onto the driveway. Otherwise the driveway to get dirty from the gutter contents and soak up the water. Again, concrete is not water-proof by itself. This downspout water in sufficient volume will erode and may discolor the concrete with impurities in the water from the gutter's contents.

If necessary, downspouts can be connected to a "flexy" elbow and then to a plastic downspout to run the water over and away from concrete and foundations.

Flexy elbow on drain allows downspout to empty into garden area and still be moved easily while gardening. Please also notice the 6 inch trough of gravel to allow water to flow off this concrete patio. This patio is going to be cleaned and possibly sealed in late spring.